In liquid crystal display (LCD) devices, LCD panels are driven by an LCD display driver. This LCD display driver is often an integrated circuit (IC) that is electrically coupled to display elements that control light modulating properties of liquid crystals. The LCD display driver is typically electrically connected to the LCD panel. Traditional techniques for connecting the LCD display driver to the LCD panel include chip on board (COB), tape automatic bonding (TAB), or chip on foil (COF). Traditional connection techniques typically result in multiple components that must be connected with a flexible film. As a result, LCD devices manufactured with traditional techniques may be expensive and bulky. COG mounting is an alternative to SMD mounting that directly mounts the LCD display driver to an overlapping edge of one of the glass panels that make up the LCD panel.
When manufacturing COG mounted LCD devices, the LCD driver is connected to a glass panel through an adhesive interconnect, e.g., anisotropic conductive film (ACF). Such an adhesive may contain electrically conductive elements, e.g., metal balls. A LCD driver has many electrical contacts for interfacing the driver IC to the LCD panel. Conductive elements in an adhesive interconnect may form electrical connections when a driver IC is pushed into the adhesive and against an LCD panel. The LCD driver may thus be adhered to the glass panel while electrical connections are simultaneously formed in the adhesive.
The electrical contact points of an adhered LCD driver are typically tested for quality assurance (QA) purposes. One such method of testing is automatic optical inspection (AOI), which uses a camera to scan the COG bond and check the quantity and shape of metal balls in the ACF. Unfortunately, AOI is slow and unreliable, often resulting in false positives. Thus, faster and more reliable techniques to test the electrical contact points for a mounted LCD driver are desired.